I experimented with it yesterday with my son at the other end.My Verizon says it is activated. However, it is greyed out on my Note 4. The Advanced Calling is turned on. What am I doing wrong?
We both have Note 4's on vzw.
He had a 4G signal and I had 3G, and the HD voice wouldn't work, nor would video call.
I went outside to obtain a 4G signal and both became available.